Two areas of theoretical population genetic research are proposed. The first concerns a number of aspects of multilocus population genetics. Among these are the elucidation of the properties of genetic modifiers of recombination in large and small populations and under a variety of natural selection regimes. The population consequences of fitness differences between genotypes in cis and trans configurations will be investigated. A new representation of general recombination schemes will be applied to the study of covariances between relatives of a quantitative character. The second area concerns traits whose transmission is both genetic and cultural. The consequences of different selection regimes and transmission patterns for the distribution of such traits within populations will be studied. Covariances between relatives will be computed in cases where transmission is influenced by interacting genes. The effect of an important culturally transmitted trait, infanticide against one sex, on the primary sex ratio in a population will be studied.